Racetrack grommet for optical fiber cable splice closure

ABSTRACT

A racetrack grommet of resilient material for use in providing a seal between two flanged closure members has first and second spaced sides thereon adapted to be positioned between the flanges, and transverse end sections having insert receiving members having bores therein. Insert members are configured to fit within the bores in end to end butting relationship to provide a seal between a cable entering or leaving the assembled closure and the insert receiving members which, in turn, provide seals for end openings in the assembled closure. The bores in the insert receiving members have holding and sealing means therein and each insert has mating means thereon for mating with the holding means to provide a seal between each of the insert members and the insert receiving member. One or more port plugs seal the unused bores in the insert receiving members. Each insert has a split thereon to facilitate insertion of a cable within the insert, and each insert receiving member has a split therein for facilitating insertion of an insert therein.

FIELD OF THE INVENTION

This invention relates to optical fiber cable splice closures and, moreparticularly, to a splice closure and components thereof which iscapable of containing a large number of optical fiber splices and whichis both low in cost and economical in installation and maintenance.

BACKGROUND OF THE INVENTION

Signal transmission through optical fibers has become, or is becoming,the dominant signal transmission mode. The bandwidth characteristics ofoptical fibers, as well as their relative immunity to certain types ofinterference and contaminants make them the desirable transmissionmedium in high capacity trunk lines as well as in lower capacity feederand distribution lines.

No matter what the intended end use may be, individual optical fibersgenerally are combined in an optical fiber cable which contains aplurality of such fibers, each of which is protected by at least onelayer of coating material. In one configuration, the fibers areassembled into groups which are held together by binder ribbons or tubesto form a cable core. This is generally enclosed in a metallic orplastic tube or jacket which, in the latter case, often contains astrength member. In another configuration, the fibers are arrayed inribbon form and the core tube contains one or more stacked ribbons.

Regardless of the cable configuration, it is usually necessary that thelengths of fiber cable be spliced at their ends to the ends of othercables, which entails splicing each of the individual fibers in a cableto a corresponding individual fiber in the second cable. To this end,there is provided a splice closure which usually comprises a protectivecase which contains at least one splice tray which, in turn, has aplurality of splice holders mounted thereon, into which the encasedindividual fiber splices are inserted and held. The cables are entrantinto the case and generally are clamped to each end thereof to reducethe effects of tensile forces on the cables and on the splices.Sufficient amounts of fiber slack must be provided for in the case, suchas, for example, half a meter of fiber length so that the individualfibers can be pulled clear of the case to effect the splice. The slackalso serves the important function of absorbing tensile forces, therebyisolating the splices from such forces. Because of the delicate andbrittle nature of individual glass fibers, they cannot be crimped orbent too sharply, i.e., bent to too small a radius of curvature, whichplaces restraints upon slack storage. Thus, there have been numerousarrangements in the prior art addressing the problem of fiber and slackstorage, as exemplified by U.S. Pat. Nos. 5,097,529 of Cobb, et al.;4,679,896 of Krafcik, et al.; and 4,332,435 of Post.

Inasmuch as, at the splice point, the cable itself is opened up and thebase fibers are exposed, the only protection afforded the fibers isprovided by the closure, which can provide only one or two layers ofprotection from the outside environment, the requirements therefor aremore stringent than for the cable, which normally provides severallayers of protection. The closure must anchor the cables stored therein,and it must be capable of withstanding torsional and axial loadstransmitted by the cable to the closure so that the splices areprotected from these loads. The closure must also seal the inner andouter sheaths of the cables and maintain the seal integrity underextreme environmental conditions. In addition, the closure must provideadequate fiber storage for slack fiber without damaging the fibers andwithout increasing signal attenuation. The closure preferably should becapable of storing any type of splice, such as, for example, discretemechanical, discrete fusion or mass mechanical, or other types whilereducing forces that tend to damage the splices. Additionally, theclosure should provide adequate grounding and anchoring for the metallicstrength members of the cable. The closure should also be capable ofaccepting high fiber count cables as well as those of low fiber count.

Typically, prior art splice closures are somewhat complex, difficult toassemble, are necessarily bulky, and, in use, difficult to access. As aconsequence, they are not economical when used for splicing relativelylow count fiber cables, such as, for example, drop cables or CATVapplications. Also, when used for low fiber count cables, the bulkinessof the closure makes it difficult to provide adequate storage room,without sacrificing accessibility. This problem of size has heretoforebeen addressed by simply using a large closure designed primarily forhigh capacity use, where feasible, or by designing special, smallerclosures for low capacity use, which cannot carry or contain largenumbers of fibers and splices.

In order to insure protection of the splices from moisture, it iscurrent practice to form the closure out of two mating halves, with agrommet therebetween, and clamp them together. Cable entry is throughopenings in the grommet, which are usually supplied with inserts whichseal the cable and in turn are sealed by the grommet. Such a grommet andinsert arrangement is shown, for example, in U.S. Pat. No. 5,472,160 ofBurek, et al.. In that arrangement, the grommet, which is of a resilientmaterial suitable for moisture sealing, has, at each end thereof, firstand second seal members having bores therein for receiving grommetinserts, which, in turn have bores therein for receiving the cable. Theseal members are preferably split longitudinally so that the grommetinserts, with cables extending therethrough, can be inserted in the sealmembers and be tightly embraced thereby. When the two halves of thehousing are clamped together, the cable is tightly embraced, as are theseal members, so that a watertight seal is achieved.

In usage, it has been found that such a sealing arrangement can bevulnerable to a bending or flexing of the cable adjacent the entrance toor exit from the closure, which can, in some instances break theintegrity of the seal. There have been various arrangements in the priorart for correcting this effect, one such arrangement being shown in U.S.Pat. No. 5,434,945 of Burek, et al. wherein the closure is encased in aprotective shell which, after assembly, is filled with an encapsulant.Such an arrangement insures that the splice closure itself is virtuallycertain to be moisture proof. However, access to the splices is mademore difficult by the presence of the encapsulant, which must be removedto permit such access. For high fiber count cables, limited access,while undesirable, does not necessarily pose too much of a problem.However, for low fiber count cables, where frequent access may often berequired, such difficulty of access is undesirable.

Cables entrant into the enclosure are preferably, and in present dayusage, almost always anchored to the splice enclosure itself, toguarantee a minimum of movement of the cable within the enclosure whichcould unduly stress the fibers and the fiber splices. One such anchoringmeans, in the form of a cable grip block, is shown in the aforementionedBurek, et al. U.S. Pat. No. 5,472,160. The grip block of that patent iscapable of adapting to cables of different sizes, and also provides ananchor for the cable central strength member which is a usual componentof loose tube type cables. The anchoring arrangement for the centralstrength member requires that the strength member or members be cut to aspecific length and bent upward into a slot within the grip member. Thestrength members are maintained within the slots against tensile forcesbecause of their rigidity and because they are bent at a right angle.Thus, they function to help maintain the cable against shifting ormovement. While this arrangement functions well, the necessity ofcutting the strength members to specific lengths and of bending andthreading them into the slots adds another increment of assembly time tothe splice closure system.

Beyond the cable grip block, the cable is opened up, i.e., the cablejacket and/or sheaths are removed to free the individual fibers so thatsplicing can be effected, commonly referred to as fiber breakout. It isgenerally necessary, or at least desirable, that sufficient amounts offiber slack be provided within the case, or enclosure as discussedhereinbefore, so that the individual fibers can be pulled clear of theclosure for preparation of the ends for splicing and for effecting thesplice. For a multifiber cable there should be, within the closure, somearrangement for positioning and storing the slack and for keeping thefibers arranged in an orderly manner. Prior art arrangements thataddress the problem of both splice and fiber slack storage andorganization are shown in the aforementioned Cobb, et al. Krafcik, etal., U.S. Pat. No. 4,332,435 of Post, as well as in U.S. Pat. No.5,420,957 of Burek, et al. As can be seen in these patents, a splicetray is used to hold and protect the splices themselves by means of asplice holder as well as providing space for the slack fibers to becontained without the necessity of too sharp bends. For example, asplice tray adapted to be mounted within the closure, as shown in theBurek, et al. U.S. Pat. No. 5,420,957 comprises an elongatedsubstantially rectangular container having circular hubs at each endabout which the fiber is to be wound, the radius of the hubs beinggreater than the critical bend radius, and a splice holder locatedbetween the hubs for containing and holding the splices. Such a tray hasbecome a widely used component of present splice closures, and, wherelarge members of splices are to be contained, various arrangements forstacking the trays may be provided as shown, for example, in U.S. Pat.No. 5,481,639 of Cobb, et al. In most of the aforementionedarrangements, the closure is designed to hold one or more splice trayshaving a specific configuration, and usually is not adaptable toaccommodating splices for different kinds of fiber configurations, e.g.,individual fibers or fiber ribbons. More particularly, it is generallyeconomically unfeasible to modify a given closure to accept more thanone type of tray.

Most of the prior art arrangements, as evident from the foregoingdiscussion, emphasize adequate storage capacity and fiber protection,with space and ease of access being secondary considerations. Certainones of the aforementioned patents, such as the Cobb, et al. patent,make size, access, and cost important considerations, at least for somesituations. However, even greater reductions in size, simplicity, andcost are needed, as well as a greater measure of versatility oradaptability coupled with a ready accessibility.

SUMMARY OF THE INVENTION

The present invention is a grommet for providing a seal between firstand second flanged closure portions wherein the closure portions defineat least one opening in an end of the closure for allowing ingressand/or egress of a cable. The grommet has first and second longitudinalsides that are spaced apart sufficiently to fit between the flanges ofthe closure portions. Transverse sections, at least one of which has aninsert receiving member with a bore therethrough, join the ends of thelongitudinal sides. Included are two insert members for insertion intothe bore, each of which has a longitudinal bore for receiving a cable.The bore of the insert receiving member has means therein for holdingthe two insert members in place in a butting end-to-end relationship.

In greater detail, the closure with which the grommet of the inventioncan be used comprises a plastic base member having a longitudinal axisand a cover member, preferably of suitable plastic material, both ofwhich are substantially identical from being molded in the same molds,thereby eliminating a major cost of differing dies. The base and cover,both of which are flanged, have the racetrack grommet of the inventionmade of, for example, polyurethane located between the flanges of thebase and cover, which are clamped together by suitable means. When thebase and cover are joined, they define a closure having a longitudinalaxis and having openings at each end of the closure which are adapted tocontain enlarged insert receiving members at the ends of the racetrackgrommet. These insert receiving members are compressed between the baseand cover to form a moisture and dirt proof seal therebetween, and aresplit longitudinally to facilitate insertion therein of cable sealinginserts. Each insert receiving member receives two sealing inserts whichare butted together longitudinally in end to end relationship and whichcontain the fiber containing cables. Each of the inserts is splitlongitudinally to facilitate insertion of the cable therein and, whenplaced within the insert receiving members of the grommet, they arerotated preferably 180° relative to each other so that the splitstherein are not aligned with each other. The use of two inserts percable insures against unseating of the inserts as a result of externalflexing force on the cable, which affect or are absorbed by the outerinsert while the inner insert remains unaffected, hence sealed. In thisway, external flexing forces do not destroy the integrity of the sealformed between the inserts and the grommet and between at least one ofthe inserts and the cable.

It will be more apparent from the following detailed description, readin conjunction with the drawings, that the racetrack grommet of thepresent invention is capable of providing a moisture and dirt-proof orcontaminant seal of high integrity for the closure and the openingstherein. The inventive aspects of the racetrack grommet and the severalcomponents thereof will be more readily understood from the followingdetailed description, read in conjunction with the following drawings.

DESCRIPTION OF THE DRAWINGS

In FIG. 1 an exploded perspective view of the splice closure of theinvention and its component parts;

FIG. 2A is a perspective view of the splice closure base member;

FIG. 2B is a plan view of the base number of the splice closure;

FIG. 2C is a side evaluation view of the base member of the spliceclosure;

FIG. 2D is an end evaluation view of the base member of the spliceclosure;

FIGS. 3A and 3B are perspective views of the cover member of the spliceclosure;

FIGS. 4A and 4B are perspective views of the cable tie retainer of theinvention;

FIG. 4C is a plan view of the cable tie retainer;

FIG. 4D is an elevation view of the cable tie retainer;

FIG. 4E is a cross-sectional view of the cable tie retainer along thelive I--I of FIG. 4D

FIG. 5A is an elevation view of one of the pedestals of the invention;

FIG. 5B is an elevation view of one of the pedestals of the inventionrotated 90° with respect to FIG. 5A;

FIG. 5C is a cross-sectional view of the pedestal along the line I--I ofFIG. 5A;

FIGS. 5D and 5E are perspective views of the pedestal of FIG. 5A;

FIG. 6A is a plan view of the racetrack grommet of the invention;

FIG. 6B is an end elevation view of the racetrack grommet of FIG. 6A;

FIG. 6C is a side elevation view of the racetrack grommet of FIG. 6A;

FIG. 6D is a cross-sectional view of the insert receiving member of theracetrack grommet along the live I--I of FIG. 6A;

FIG. 7A is an elevation view of an insert for use with the grommet ofFIG. 6A;

FIG. 7B is an end elevation view of the insert of FIG. 7A;

FIG. 7C is a cross-sectional view of the insert along the live I--I ofFIG. 7B;

FIG. 8A is an elevation view of a port plug for use with the grommet ofFIG. 6A;

FIG. 8B is an end elevation view of the port plug along the line I--I ofFIG. 8A;

FIG. 8C is a cross-sectional view of the port plug of FIG. 8A

FIG. 9A is a perspective view of the central strength member (CSM)anchor of the present invention;

FIG. 9B is a plan view of the CSM anchor of FIG. 9A;

FIG. 9C is an end evaluation view of the CSM anchor of FIG. 9A;

FIG. 9D is a side evaluation view of the CSM anchor of FIG. 9A;

FIG. 9E is a plan view of an alternative configuration of the CSManchor;

FIG. 9F is an end elevation view of the CSM anchor of FIG. 9E;

FIG. 10A is a perspective view of the splice tray adapter plate of theinvention;

FIG. 10B is a plan view of one side of the splice tray adapter plate ofFIG. 10A;

FIG. 10C is a side elevation view of the splice tray adapter of FIG.10A;

FIG. 10D is an end elevation view of the splice tray adapter plate ofFIG. 10A;

FIG. 11 is a perspective view of the splice tray adapter plate mountedon the pedestals, illustrating how one side thereof accommodates twostandard (UCB) splice frays;

FIG. 12A is a plan view of a discrete splice tray for use with theinvention;

FIG. 12B is a side elevation view of the discrete splice tray of FIG.12A;

FIG. 12C is an end elevation view of the discrete splice tray of FIG.12A;

FIG. 12D is a perspective view of the discrete splice tray of FIG. 12A;

FIG. 13A is a perspective view of the mass splice tray of the invention;

FIG. 13B is a plan view of the mass splice tray of FIG. 13A;

FIG. 13C is a side elevation view of the mass splice tray of FIG. 13A;

FIG. 13D is an end elevation view of the mass splice tray of FIG. 13A;

FIG. 14A is a perspective view of an insert for use with the mass splicetray of FIG. 13A, for holding one type of splice holder;

FIG. 14B is a plan view of the insert of FIG. 14A;

FIG. 14C is an end elevation view of the insert of FIG. 14A;

FIG. 14D is a side elevation view of the insert of FIG. 14A;

FIG. 14E is a detail of one of the locating members of the insert ofFIG. 14A;

FIG. 15A is a perspective view of splice holders mounted in the insertof FIG. 14A;

FIG. 15B is a plan view of the splice holders mounted in the insert ofFIG. 14A;

FIG. 15C is a side elevation view of the splice holders mounted in theinsert of FIG. 14A;

FIG. 16A is a perspective view of another form of insert for use withthe mass splice tray of FIG. 13A;

FIG. 16B is a plan view of the insert of FIG. 16A;

FIG. 16C is an end elevation view of the insert of FIG. 16A;

FIG. 16D is a side elevation view of the insert of FIG. 16A;

FIG. 16E is detail of one of the locating members of the insert of theinsert of FIG. 16A;

FIG. 17A is a perspective view of a splice holder mounted in the insertof FIG. 16A;

FIG. 17B is a plan view of the holder and insert combination of FIG.17A;

FIG. 17C is a side elevation view of the holder and insert combinationof FIG. 17A;

FIG. 18A is a plan view of a cover member for the mass splice tray ofFIG. 13A;

FIG. 18B is a side elevation view of the cover member of FIG. 18A; and

FIG. 19 is a perspective view of the mass splice tray of FIG. 13Ashowing at least a partial routing of the fiber ribbons therein relativeto the splice holder.

DETAILED DESCRIPTION

In FIG. 1 there is shown an exploded view of the splice closure assembly11 of the present invention, and the various component parts thereofwhich, when assembled, make up a complete splice closure assembly.

Closure assembly 11 comprises a base member 12 and a cover member 13which is designed to be bolted or otherwise clamped to base member 12after the components have been assembled with the cables, opticalfibers, and splices, none of which are shown, in their assignedpositions. Both base member 12 and cover member 13 are preferably madeof suitable plastic material having strength and rigidity sufficient towithstand external shocks without compromising the closure integrity, orwithout affecting the internal components of the assembly. As a costsaving measure, both base member 12 and cover member 13 are molded orotherwise formed in substantially identical molds or dies, and are,themselves, substantially identical to each other, as will be moreapparent hereinafter.

Base member 12 has a deep trough-like configuration with first andsecond longitudinally extending flanges 14 and 16 leaving a plurality ofbolt holes 17 which match corresponding bolt holes 18 in flanges 19 and21 of cover member 13. Bolts 22 and nuts (not shown) fit into thematching holes 17 and 18 for clamping the two members 12 and 13together. It is, of course, to be understood that other types ofexternal clamping means might readily be used in place of bolts 22. Sideby side end compartments 23,24 are formed at each end of base member 12by means of walls or septa 26 and 27 which have semi-circular cut-outstherein for receiving the insert receiving members 28 and 29 of a racetrack grommet 31, having bores therethrough for inserts 32 and 33.Grommet 31, which is made of a suitable flexible, compressiblepolyurethane material functions as a sealing gasket between the flanges14 and 19 and 16 and 21 between base member 12 and cover member 13. Eachof the insert receiving members 28 and 29 has a pair of longitudinallyspaced V-shaped grooves 34 in the bore thereof, only one of which isvisible in FIG. 1. Each of the inserts 32 and 33, both of which arepreferably made of polyurethane, has a V-shaped ridge 36 around thecircumference thereof which is adapted to fit within one of the grooves34. In order that insertion of inserts 32 and 33 into receiving members28 and 29 might be more easily accomplished, each of the receivingmembers 28 and 29 is split longitudinally by slits 37.

Each of the inserts 32 and 33 has a bore 38 extending therethrough forreceiving the cable, not shown, which is to be spliced. As will beapparent hereinafter, each of the inserts 32 and 33 is splitlongitudinally by splits 39, 41 to facilitate insertion of the cabletherein, and, during assembly, the slits 41 in inserts 33 should berotated by preferably 180° relative to the slits 39 in inserts 32 sothat there is no straight through path for moisture to enter the closurefrom the outside. The use of two inserts arrayed end-to-end in buttingrelationship helps avoid breaking of the moisture seal or barrier as aresult of flexing of the external portion of the cable. Even undersevere flexing, which might cause inserts 33 to be displacedsufficiently to break the seal between the cable and the insert 33, orbetween the insert 33 and receiving member 29, the inner insert 32 isnot affected, and the integrity of the seal, which results from thecompressive forces on the grommet 31, receiving members 29 and inserts32 and 33 when base member 12 and cover member 13 are clamped together,is not affected. In a similar manner, the slits in both inserts 32 and33 should be rotated relative to the slits 37 in receiving members 28and 29.

When only one cable is to be inserted into the closure assembly 11,through, for example, receiving member 29 as shown in FIG. 1, a portplug 42 is inserted into receiving member 28 to create a moisture proofseal. Thus, both ends of the closure assembly 11 will, upon assembly,have moisture proof seals, whether one or two cables are passedtherethrough.

Within the closure assembly 11, more particularly, within base member12, is mounted a grip block assembly 43 which preferably is the same as,or similar to, the grip block assembly shown, for example, in Burek etal. U.S. Pat. No. 5,440,666. Grip block 43 is shown aligned with insertreceiving member 29 and insert 32 so that the cable entrant throughinsert 32 passes directly into grip block assembly 43. The grip block ismounted on a pair of studs 44, 46 which, in turn, are mounted inelongated bosses 47 and 48. A grip block 43 is shown in FIG. 1 in itsmounted position adjacent compartment 24 but separated therefrom by wall27. Grip block 43 performs the function of tightly gripping the cableentrant into the closure assembly in the manner shown and described inthe aforementioned Burek et al. U.S. Pat. No. 5,440,666 so that thecable is immobilized. When the cable has a loose tube configurationhaving a central strength member, it is desirable that the centralstrength member, which is usually, but not always, a relatively stiffmetallic wire member, be anchored. To this end, a central strengthmember anchor 49 is mounted below grip block assembly 43 and held inplace thereby, and extends inwardly therefrom. Anchor 49, which will bediscussed in greater detail hereinafter, has a bore 51 substantiallyaxially aligned with the cable held by grip block 43 for receiving thecentral strength member of the cable, and further has means for clampingthe central strength member to immobilize it and the cable stillfurther.

Along the interior side walls of base 12 are arrayed spaced built outslots 52, only one of which is clearly shown in FIG. 1 into which cabletie retainers 53 are inserted. Cable tie retainer 53 make it possible toorganize the interior of the closure assembly 11 by tying the cable orthe fibers, in bunches, to the walls of the closure 11, thereby makingit possible to route the fibers or cable along the walls to preventtheir becoming tangled or otherwise interfering with the othercomponents.

On the interior floor of base member 12 are mounted first and secondpedestals 54 and 56, only pedestal 54 being completely shown. Pedestals54 and 56, which will be discussed more fully hereinafter, aresubstantially cylindrical in shape and have, at their distal endsresilient fingers 57, 58 which are adapted to hold a splice tray adapterplate 59, thereby affording a unique mounting arrangement for one ormore splice trays 61. The spaced pedestal arrangement makes it possibleto store fiber slack by winding the fibers about the pedestals 54, 56,preferably in a figure eight (8) configuration, but many otherconfigurations are possible. To this end, and to prevent too sharpbending of the fibers, the radius of the cylindrical pedestals 54, 56 isgreater than the critical bend radius of the fibers. In order that thefibers may be brought from the space below, past the splice tray adapterplate 59 up to the splice tray 61 mounted thereon, plate 59 has arectangular shaped cut-out 62 along one side, as shown, and splice tray61 has a matching cut-out portion 63. A recessed lid 64 is provided forsplice tray 61 which becomes nested into the splice tray above it whenthe splice trays are stacked.

In order that the closure assembly 11 may be affixed to, for example,overhead cabling, or otherwise mounted to a support structure, flangemember 14 has projecting mounting tabs 64. These tabs 64, whichpreferably are of the same material as other fastening hardware, allowthe closure to be racked in a manhole or hung on an aerial strand.

Closure Base and Cover

FIGS. 2A through 2D are different views of base member 12, and FIGS. 3Aand 3B are two perspective views of cover member 13, which, together,form the closure shell of the assembly 11. As can be seen from thosefigures, both base 12 and cover 13 are substantially identical in size,shape, and conformation, and generally comprise externally ribbed (forstrength) shells of suitable plastic material. The same or similar diesmay be used in molding members 12 and 13, however, base member 12 hasadditional elements not present in cover member 13. As can be seen incomparing FIGS. 2A and 3A, base member 12 has four elongated bosses 47and 48 arrayed thereacross at each end adjacent wall 26 and 27 on theinterior side thereof. Each pair of bosses 47 and 48 are joined by across shaped support member 66 which has a forward or inward projectingarm 67 and a rearward projecting arm 68. Arms 67 and 68 are best seen inFIG. 2B. For reasons which will be apparent hereinafter, arm 67 islonger than, and projects above, arm 68. The cross arms 71 and 72between each of the bosses 47 and 48 likewise are shorter than arm 67.The innermost bosses 47 are joined by a septum or wall 73 which isspaced from wall 26 as best seen in FIG. 2B. The other end of basemember 12 has the same configuration of bosses 47, 48, cross-shapedsupport members 66 and septum 73 as best seen in FIG. 2B. Studs 44 and46, which are threaded, are preferably affixed in elongated bosses 47and 48, respectively, during the molding process, to create a rigidconnection of the studs to base member 12.

First and second spaced bosses 77 and 78 are located on the inner floorof member 12, and threaded studs 79 and 81 are affixed therein,preferably in the same manner as the studs 44 and 46. Bosses 77 and 78and studs 79 and 81 are preferably aligned with the longitudinalcenterline of member 12, and spaced as shown. It is important that noneof the studs penetrate the wall of member 12, hence the method ofplacing them in position during the molding process is to be preferred.

At each end of member 12 are arrayed locating holes 74 which aredesigned to mate with bolt locations 76 on cover member 13, as best seenin FIG. 3A. In addition, bosses 75, having bores therein, are providedat each end to receive bolts 70 shown in FIG. 1, and cover member hasbosses 80 having bolt holes extending therethrough. Bosses 75 preventover compression of grommet 31 by bearing against bosses 80.

Built out slotted members 52 are formed along the two interior sidewalls of member 12, in spaced array, as shown. Members 52 are adapted toreceive and retain cable tie retainers 53, the configuration of each ofwhich is best seen in FIGS. 4A through 4E. Tie retainer 53 has a roughlyT-shaped configuration with the cross piece 82 having elongated bores 83and 84 at the distal ends thereof for receiving cable (or fiber) ties.The depending portion 86 also has a roughly T-shaped configurationdesigned to slip within the slot formed by member 52. The leg 87 ofportion 86 is curved to facilitate insertion into the slot formed bymember 52, and is provided with first and second barbs 88 and 89 which,when retainer 53 is inserted fully into slotted member 52 are designedto break off within the slot, thereby insuring that retainer 53 isfirmly held within member 52. As was pointed out hereinbefore, cable tieretainer 53 is useful in organizing and routing cable and fiber. Theties can be wrapped around the fiber bunch, for example, and threadedthrough bores 83 and 84, thereby making it possible to snug the cable orfibers close to the side walls of base member 12.

First and second pedestals 54 and 56 are identical, and theirconfiguration is shown in FIGS. 5A through 5E. Each of the pedestals 54and 56 is designed to be mounted to one of the studs 79 and 81 by meansof a threaded bore 91 in the bottom 92 or by other suitable means, suchas a nut; not shown. Each pedestal is aligned or oriented properly bymeans of an alignment hole 93 in the bottom 92 which mates with analignment pin 94 on the bottom floor of member 12. Each pedestal whichis of a suitable plastic material has a substantially hollow cylindricalshape, the raidus of curvature of which is greater than the criticalradius for the optical fibers, and has formed at the distal end thereof,by means slits 96 and 97, resilient fingers 57 and 58, the distal ends98 and 99 of which have formed thereon latch projections 101 and 102designed to mate with splice tray adapter plate 58, as will be discussedmore fully hereinafter. The use of pedestals 54 and 56 for holding thesplice tray adapter plate 58, and hence, the splice tray or trays abovethe floor of member 12 provides a substantially empty space of largevolume defined by the side and end walls and the floor of member 12 forstoring slack fiber. The fiber is wound in a FIG. 8 configuration orother chosen configurations previously discussed about the pedestals 54and 56 and thus is prevented from becoming tangled or otherwisedisorganized.

The cover member 13, shown in FIGS. 3A and 3B is, as has been discussedhereinbefore, adapted to fit, flange to flange with base member 12, withthe racetrack grommet therebetween to provide a moisture and dirt proofseal.

The fiber closure assembly 11 including pedestals 54 and 56, splice trayadapter 59 and discrete splice tray 61 are the basis of U.S. patentapplication Ser. No. 08/847,214, filed concurrently herewith.

Racetrack Grommet and Inserts

Racetrack grommet 31, which is shown in detail in FIGS. 6A through 6Dcomprises a substantially rectangularly shaped member 103 of suitableflexible, resilient material, preferably polyurethane, havinglongitudinal sides 104 and 106 which are spaced apart a distance suchthat they fit between the flanges 14 and 16 on base 12 and 19 and 21 oncover member 13 and are substantially co-extensive therewith. Also,sides 104 and 106 have a plurality of bolt holes 107 which are spacedand located to be coincident with the holes 17 and 18 in the flanges ofbase member 12 and cover member 13. In some cases, bolts may not be thepreferred way of clamping the base and cover member together, in whichcase the bolt holes 107 might not be needed. An alternative clampingarrangement is shown in U.S. Pat. No. 5,434,945 of Burek et al.. At theends of member or grommet 103 are transverse section 108 and 109, whichare substantially identical, each of which comprises spacedcylindrically shaped insert receiving members 28 and 29 separated by aweb 111. Web 111 has a bolt hole 112 extending therethrough whichcoincides with the holes in bosses 75 and 80 of base member 12 and covermember 13 respectively. The bolts 70 produce clamping along thecenterline of the closure 11, thereby insuring a tight seal throughout,in conjunction with the bolts 22. Thus, any bowing or warping of eitherthe base member 12 or cover 13 is prevented, or minimized. Each of theinsert receiving members 28 and 29 has a bore 115 extending therethroughfor receiving the grommet inserts 32 and 33 and a longitudinal slit 37to facilitate insertion of the inserts therein for holding the insertsin place, as will be discussed hereinafter.

An insert 32 for a receiving member 28 or 29 which is preferably of thesame material is shown in FIGS. 7A, 7B, and 7C and comprises acylindrical body 113 having a cable receiving bore 38 extendingtherethrough. Within bore 38 are a plurality of flexible sealing flangesor fingers 114, which are, as best seen in FIG. 7C, preferably slopedtoward the cable entrance end of insert 32, and body 113 has alongitudinal slit 116 therein. In practice, when a cable is to beinserted into bore 38, the insert is spread apart at the slit 116 andthe cable is forced into bore 38 past the sealing fingers 114. Aftercable insertion, and insertion of insert 32 into receiving member 28 or29, the fingers 114 are compressed to produce a tight seal against thecable outer jacket. The outer surface of body 113 has a V-shapedcircumferential ridge 36 which nests in V-shaped groove 34 in insertreceiving member 28 or 29 to hold it in place longitudinally, and,incidentally, to form a moisture block. As was discussed hereinbefore,each of receiving members 28 and 29 is dimensioned and configured tohold two inserts 32 and 33, which are identical, in butting or back toback relationship. Thus, the spacing between the V-shaped grooves 34 isapproximately equal to the length of an insert 32 when the V-shapedridges 36 are centrally located on insert 32, as shown. As pointed outhereinbefore, it is desirable that the slit 116 in one insert 32 berotated, preferably 180°, to a different orientation than the slit 116in abutting insert 33, thereby avoiding a direct moisture path into theinterior of the closure assembly 11.

When assembly of the closure 11 is complete, the compression forces onthe resilient grommet 31, receiving members 28 and 29, and inserts 32and 33 insure that the slits 37 and 39 cannot open. However, if a cablepassing through a pair of inserts 32, 33 undergoes external flexing ortwisting closely adjacent to the closure 11, the forces on the outerinsert 33 might be great enough to distort it thereby possibly openingit at the slit 39 or possibly unseating it within member 28 or 29,thereby destroying the integrity of its seal. The arrangement of thepresent invention wherein two inserts 32, 33 are used, allows the outerinsert 33 to absorb any such external forces while the inner insert 32is not subjected thereto, and hence, its seals remain unbroken.

In use, the assembly 11 may have only one cable entrant therein, or onlyone cable exiting, in which case one or more of the insert receivingmembers 28, 29 will not require the inserts 32, 33. However, the idlereceiving member 28 or 29 must be sealed off to prevent the intrusion ofmoisture, dirt, or other contaminants into the closure interior. To thisend, there are provided one or more port plugs 42, the configuration ofwhich is shown in FIGS. 8A, 8B, and 8C. As can be seen in the figures,plug 42, which is preferably of the same material as base 12 and cover13 and, is in the form of a hollow cylinder having a closure end wall117 and a side wall 118 tapered in the interior of plug 42, as best seenin FIG. 8C. In addition, the exterior surface of plug 42, which isdimensioned to fit within a receiving member 28 or 29, has first andsecond V-shaped ridges 119 and 121 which are spaced to coincide withV-shaped grooves 34 in receiving member 28 or 29, and dimensioned to fitsnugly therein. The tapered wall 118 which is thinner at the open endthan at the closed end 117, facilitates insertion of the plug 42 intomember 28 or 29, with the open end toward the interior of the closure11, and end wall 117 facing the exterior. In this manner, unusedreceiving members 28, 29 are sealed so that the interior of closure 11is not affected by ambient atmospheric conditions.

The combination of the racetrack grommet 31, inserts 32, 33, and portplugs 42 insure substantially complete sealing of the interior ofclosure 11.

The unique principles, construction and operation of the racetrackgrommet, the inserts, and the port plugs are shown as used with aparticular closure design. However, it will be clear to workers in theart that these features can readily be adapted to other types ofclosures than the one shown.

Central Strength Member Anchor

In FIGS. 9A through 9E there are shown various views of the centralstrength member (CSM) anchor 49, and of an alternative embodiment 122thereof. As was pointed out hereinbefore, anchor 49 functions as ananchor for the central strength member of, for example, a loose tubecable, without requiring precise cutting or bending of the CSM.

Anchor 49, which is preferably of a hard plastic material, comprises anelongated base portion 123, an upstanding leg 124, and a CSM receivingmember 126 having a bore 127 extending therethrough for receiving theCSM of the cable. Member 126 has first and second threaded bores 128 and129 for receiving set screws 130 and 135 which clamp down on the CSM tohold it firmly in place within bore 127. Thus, the CSM is anchoredfirmly within the bore 127, which functions not only to contain the CSMbut also add another point of resistance against tensile forces on thecable. Base portion 123 comprises a substantially rectangularly shapedplanar member 131 from which depends side walls 132 and 133. Disposedalong the center line of anchor 49 are first and second rectangularholes 134 and 136 which pass completely through member 131 and which aredimensioned to fit snugly over arm 67 of support member 66 which isshown in FIG. 2B. Each of the depending walls 132 and 133 has first andsecond slots 137 and 138 which are dimensioned to fit down over crossarms 71 and 72 when arm 67 penetrates one of the rectangular holes 134,136 as explained in the foregoing. Each of the side walls 132 and 133also has a slit 139 and member 131 is transversely scored at 141, thescore 141 being aligned with slits 139. Slits 139 and score 141 allowthe portion of base portion 123 to be broken off so that the slots 137are to be fitted over cross arms 71 and 72 and rectangular hole 134 fitsover arm 67. If, on the other hand, it is desired to have a greaterlength of the cable central strength member protruding from grip block43, the member 123 is not broken, i.e., shortened, and slots 138 andrectangular hole 136 become functional in mounting anchor 49 to basemember 12. Anchor 49 is, when the closure is assembled, located undergrip block 43 and held in place thereby when block 43 is mounted to thebase 12. The height of arm 124 is chosen such that when anchor 49 ismounted in place, the bore 127 will be approximately aligned with theaxis of the cable held in grip block 43 so that it will not be necessaryto bend the cable central strength member in order to anchor it.Further, the use of an elongated base portion 123 with the scoring 141and the slits 139 in side walls 132 and 133 makes possible a wider rangeof CSM lengths, thereby minimizing the restraints on cutting the CSM toa proper length. The anchor 49, which is a separate entity from gripblock 43, makes possible a simple and quick anchoring of the CSM.

FIGS. 9E and 9F depict a modification of the anchor member 49 which iscapable of gripping two CSM's. For simplicity, like parts to those inFIGS. 9A, 9B, 9C, and 9D, bear the same reference numerals. The anchormember 142 comprises a base portion 123 which comprises a planar member131 and copending side walls 132 and 133. However, one end of planarmember 131 is bifurcated to form two arms 143 and 144, each one of whichterminates in an upstanding leg 124 having a CSM receiving member 126 onthe distal end thereof. Member 123 is shown with a third rectangularhole 146 and a second scoring 147 on the surface of planar member 131,thereby allowing greater flexibility in anchor length. Such an anchormember is especially useful in those closure assemblies where the gripblock 43 or an equivalent cable gripping member is designed toaccommodate two cables. The spacing of the two CSM receiving members 126are chosen to be such that they are approximately aligned with the cableaxes, thereby eliminating the necessity of precisely bending the cableCMS's.

The CSM anchor as shown and described herein greatly simplifies theassembly of the closure with cables entrant therein. Where, as ispossible in the case of the assembly shown in FIG. 1, four cables areentrant into the closure, four CSM anchors 49 would be used. On theother hand, some closure configurations can accommodate greater numbersof cables, in which case, anchor 142 would be used, or, in somearrangements, a combination of anchors 49 and 142 can be used. Themounting arrangement for both anchors 49 and 142 are for the particularclosure 11 as shown in FIG. 1. It will be apparent that other mountingarrangements for the anchor 49 and 142 might be used, depending upon theparticular closure configuration. The unique CSM anchor as depicted anddescribed herein is the basis for U.S. patent application Ser. No.08/846,409 of Burek et al.

Splice Tray Adapter Plate

In FIGS. 10A through 10D there is shown in greater detail the splicetray adapter plate 59 which mounts upon the tops or distal ends of thepedestals 54 and 56. As was discussed in the foregoing, and as will bereadily apparent hereinafter, adapter plate 59 can accommodate twostandard splice trays of the type shown in the aforementioned Burek etal. U.S. Pat. No. 5,420,957, or more than two when the trays arestacked, as well as one or more stacked discrete splice trays 61 or masssplice trays.

Adapter plate 59 comprise a thin rectangular plate 147 of suitablematerial, preferably a hard plastic, which is preferably ribbed, asshown, for added stiffness and resistance to warping or bowing. Firstand second spaced openings 148 and 149, substantially rectangular inshape but having curved ends are oriented as shown along the centerlineof member 147. The spacing between openings 148 and 149 corresponds oris equal to the spacing between pedestals 54 and 56, and each opening149 and 149 has, at each end thereof, a projecting lip 151 which isadapted to be engaged by one of the latch projections 101 or 102 on thedistal ends of resilient fingers 57 or 58 of the pedestals 54 and 56. Inthis manner, plate 59 can be mounted on and removably affixed to thepedestals 54 and 56. At two of the corners 152 and 153 of the platemember 147 are pivot pin receiving bushings 154 and 156 which receivepivot pins on the splice tray 61 or other splice trays, as will beapparent hereinafter. Bushing 154 is, preferably, fixed in place atcorner 152 while bushing 156 forms the end of a resilient finger 157which extends from the side of plate member 147 toward corner 153. Thus,in mounting a splice tray to adapter plate 59, finger 157 can be flexedto permit easy insertion of a splice tray pivot pin therein. At each endof plate member 147 is a flange member 158 or 159, and at each end ofeach flange member are pivot pins 161 and 162, which are also used inmounting a splice tray on plate 59. At the other two corners ofrectangular plate 147 are latch holes 150 for latching a mounted splicetray, such as tray 61, to adapter plate 59.

Extending from flanges 158 and 159 and located substantially centrallybetween pins 161 and 162 are first and second L-shaped latch members 163and 164. As viewed in FIG. 10B and 10D, the legs 166, 167 of members 163and 164 extend across the thickness of flanges 158 and 159, while theprojecting arms 168 and 169 are aligned with the bottom thereof. As willbe apparent hereinafter, when either the discrete splice tray 61 or themass splice tray for use with plate 59 is mounted, latch members 163 and164 play no part in affixing such splice tray to adapter plate 59.However, when standard or UCB splice trays are to be mounted, theadapter plate is inverted so that arms 168 and 169 are aligned with thetop of flanges 158 and 159, and latch members 163 and 164 act to latchthe splice trays in place. This is illustrated in FIG. 11, which depictsadapter plate 59, mounted on pedestals 54 and 56 in its invertedposition where the L-shaped latch members 163 and 164 (only 163 beingshown) are in their inverted position, with the arm 168 being at the topof the inverted L. First and second UCB type splice trays 171 and 172are mounted on the pivot pins 161 and 162, and resilient latches 173 and174 on each splice tray engage the arms 168 and 169 of latch members 163and 164. Thus, adapter plate 59 can accommodate two splice trays 171 and172 on a single level, and the splice trays may be stacked in accordancewith present practice.

One elongated side 176 is provided with a cut-out portion 62 which formspassage for the fibers to be spliced from below the adapter plate 59 tothe splice trays, as shown in FIG. 12D.

Plate 59 also has a centrally located bore 155 therein which is usefulfor mounting bolt or stud mounting splice trays thereto.

Discrete Splice Tray

The discrete fiber splice tray 61 for use with adapter plate 59 inclosure 11 is shown in detail in FIGS. 12A through 12D. Tray 61comprises a base member 177 of suitable rigid plastic material having afloor 178 along which are arrayed a plurality of splice holder regions179 upon which splice holder 181, shown diagrammatically in FIG. 12D areto be affixed, as by adhesive. The splice holders 181 as depicted inFIG. 12D are for illustrative purposes only, the actual splice holdershaving more slots for splices than are shown, and being configured fordifferent types of splices. Extending upwardly from the peripheral edgesof floor 178 are front, rear, and side walls 182, 183, and 184,respectively. The designation "front" and "rear" are only applicable tothe view of the splice tray shown in FIGS. 1 and 12D, there being noactual "front" and "rear". Extending from the top edges of walls 182,183, and 184 are a plurality of protective tabs 186 which function tohold the fibers within the confines of the walls by preventing them frombulging or bending upward, as best seen in FIG. 12D. Tray 61 also has arecess opening 63 which, when tray 61 is mounted on adapter plate 59 onthe obverse side thereof, coincides with opening 62 in plate 59 to allowfiber to be fed to the tray from below adapter plate 59. First andsecond channels 187 and 188 are open to the recess opening 63 andfunction to route the fibers into the confines of the walls 182, 183,and 184. Because the fiber slack is stored below the adapter plate, asdiscussed in the foregoing, it is not necessary that the splice tray 61have hubs at each end, as is typical of the UCB tray and most other inthe prior art. This represents a substantial savings in fabrication,since the dies or molds for the tray 61 are much simpler andcorrespondingly, less costly than those for prior art trays.

Located at the corners formed by side walls 184 and the walls 189forming channels 187 and 188 are pivot pins 191 which are designed tofit within pivot pin bushings 154 and 156 on adapter plate 59, therebypivotally mounting splice tray 61 to plate 59. As pivot pin bushing 192formed on the distal end of a flexible finger 193 is located immediatelyabove the other pivot pin 191. Bushings 192 and 194 are adapted toreceive the pivot pins of a second splice tray (not shown) in the eventthat it is necessary or desirable to stack several splice trays 61.Splice tray 61 is provided with a recessed cover 64, as shown in FIG. 1,which is used with every tray in a stack. At the other two corners oftray 61 are resilient latching fingers 190 whose distal ends have lippedlatches 195 which are designed to mate with latch holes 150 in adapterplate 59 to hold tray 61 securely in place.

As can best be realized from FIG. 12D, the discrete splice tray 61 cancontain a large number of discrete splices contained in holders 181, andonly that portion of the fibers themselves contained therein is thatrequired to accommodate the splices, without any additional slackstorage.

Mass Splice Tray

The closure assembly 11, as pointed out in the foregoing, is, throughits unique combination of pedestals 54 and 56 and adapter plate 59,capable of accommodating several different types of splice trays whileproviding large amounts of fiber storage space. In addition to itsability to organize optical fibers and fiber slack, it is also equallycapable of organizing and storing or containing optical fiber ribbonstructures and slack ribbon. Inasmuch as optical fiber ribbons containlarge numbers, e.g., twelve, fibers therein, it is desirable thatadditional slack containment be provided to facilitate splicing of thefibers within the ribbon.

In FIGS. 13A through 13G there is depicted a mass splice tray 196, ofsuitable material such as thin, hard plastic, which is designedprimarily to contain optical fiber ribbon splices of differing typeswhile, at the same time, storing ribbon slack without creating two sharpbends in the ribbons.

As best seen in FIG. 13A, tray 196 comprises a planar floor member 197of substantially rectangular shape having a front wall 198, a rear wall199, and first and second end walls 201 and 202. It can be seen that thewalls are substantially higher than the side and end walls of thediscrete splice tray 61. The terms "front" and "rear" refer only to thepositions of walls 198 and 199 as viewed in FIG. 13A. End walls 201 and202 have extensions 203 and 204, respectively, from which project walls206 and 207 which form channels 208 and 209 for routing the fiberribbons from below the adapter plate 59 to the interior of tray 196, asdefined by the walls thereof. Protective tabs 211 extend from the upperedges of the several walls to prevent the fibers or ribbons from bulgingor bending upward, thereby maintaining them below the top edges of thewalls of the tray 196. The top edge of front wall 198 has first andsecond spaced latch projection 212 and 213 which, as will be apparenthereinafter, function to hold a cover member in place. At the rearcorners of extensions 203 and 204 are similar projections 215 which alsofunction to hold the cover member in place. At either end of front wall198, at the bottom thereof, is a resilient finger 214, the distal endWhich has a projecting latch member 216 adapted to mate with theopenings 150 in adapter plate 59 to affix the splice tray 196 into placeon plate 59. At the intersections of end walls 201 and 202 with frontwall 198 are first and second curved sections 217 and 218, which haveextending flanges 219 and 221, each have a hole 222 at the cornerthereof which is adapted to receive the latch members 216 on a secondsplice tray when the trays are stacked for additional capacity. At thelower corner of each of extensions 203 and 204 is a projecting pivot pin223 which is designed to fit within one of the bushings 154 or 156 onadapter plate 59. On extension 204 is formed a resilient finger 224which has, at its distal end, a pivot pin bushing 226, located directlyabove pivot pin 223. Also, on extension 203 there is formed a pivot pinbushing 227. Bushings 226 and 227 are adapted to receive the pivot pins223 of a second tray that is stacked upon the tray 196 so that it ispivotable with respect thereto, and pins 223 on tray 196 serve to mountit pivotably to adapter plate 59.

Extending from rear wall 199, and approximately centrally located withrespect thereto is a splice holder support shelf 228 which is spacedfrom floor 197 and supported in part by a curved support member 229.Rear wall 199 has first and second slots 231 and 232 which are spacedapart a distance approximately the width of support shelf 228 and arealigned with the extending sides thereof, and which extend from the topedge of wall 199 approximately to the top surface of shelf 228, as bestseen in FIG. 13A. Shelf 228 is designed to support any one of a numberof types of splice holders, as will be apparent hereinafter, and slots231 and 232 function to position the splice holders relative to theshelf 228.

The front wall 198 has depending therefrom spaced locating tabs 233which are adapted to bear against the front edge of adapter plate 59,thereby locating tray 196 relative to the plate 59. End walls 201 and202 each have a depending tab 234 which are adapted to fit withinlocating holes 236 in adapter plate 59, the further to assist inlocating tray 196 on plate 59.

In FIGS. 14A through 14E there are shown several views of a spliceholder insert 237 for mounting a splice holder with foam material forcushioning the splices, as shown in FIGS. 15A through 15C, onto masssplice tray 196. Insert 237, which is preferably made of a hard plasticmaterial, comprises a floor member 239 having a front wall 241, anintermediate wall 242, and a rear wall 243, which is, as shown in thefigures, wider than the floor 237 and walls, each of which isapproximately as wide as the support shelf 228. Extending from the rearof wall 243 are first and second T-shaped locating members 244 and 246,with the legs of the T-shapes being spaced apart a distance equal to thespacing of the locating slots 231 and 232. The leg of member 244 isadapted to slip into slot 231, and the leg of member 246 into slot 246so that insert 237 can be lowered onto shelf 229 and be held therebymembers 244 and 246 in the slots 231 and 232 respectively. As shown inFIGS. 15A through 15C, two fusion splice holders 238 can be fitted ontoinsert 237, and held in place by, for example, suitable adhesive means,not shown, such as a double sided adhesive tape or a suitable cement.Each splice holder 238 is preferably made of a soft, resilient foammaterial and comprises a plurality of slots 247 separated by bands 248.The slots or grooves 247 are each adapted to hold an encased fusionsplice therein and, because of the resilience of the holder material, togrip it firmly. As an example, each holder 238 may have six slots 247 sothat twelve fusion splices may be contained on one insert. The inserts237 may be stacked so long as there is room in slots 231 and 232 for theT-shaped members 244 and 246 of each insert, thereby greatly increasingthe member of splices held. Inasmuch as a typical fiber ribbon containstwelve fibers, for example, two stacked inserts can contain two hundredand eight-eight fiber splices.

In FIGS. 16A through 16E there is shown an insert 249 which isconfigured to hold a mechanical splice holder 251 as shown in FIGS. 17Athrough 17C. Insert 249 which, like insert 237 is preferably made of asuitable hard plastic material, comprises a floor 252, a front wall 253and a rear wall 254. Insert 249, because of the configuration of spliceholder 251, is wider than the shelf 228 of tray 196. On the rear of wall254 are first and second T-shaped locating and holding members 256 and257 which function in the same manner as explained with reference tolocating and holding members 244 and 246. Insert 249 also has first andsecond shallow side walls 258 and 259 which assist in holding the spliceholder 251 in place on insert 249. As can be seen in FIGS. 17A through17C, the mechanical splice holder 251 is depicted as mounted on insert249 and comprises a plurality of off-set cavities 261 which are designedto hold the encased mechanical splices. Holder 261 is preferably made ofa soft, resilient foam material that grips the encased mechanicalsplices. Fiber ribbon entrance into and exit from each of the cavities261 is via slits 262 and 263 cut in the material of holder 251. Anadvantage of such an arrangement is that the slits 262, and 263 allowthe holder to orient and hold the fiber ribbons leading to the splicesand exiting therefrom.

In FIG. 18 there is depicted a cover member 264 for tray 196. Covermember 264 which is preferably made of a transparent plastic materialhas first and second tabs 266 and 267 designed to hit againstprojections 212 and 213 on tray 196, and act as a means of squeezing thecover so that it bends upward and shortens its width so that it can beeasily removed from the splice tray and the rear edges 268 slip underprojections 215 on tray 196. Cover 264 also has a cut-out or recessedportion 269 to afford clearance for fiber ribbons being routed frombelow the adapter plate 59 to a second splice tray 196 stacked upon thefirst tray 196.

FIG. 19 is a perspective view of the mass splice tray 196, with a singlefusion splice tray 238 and insert 237 mounted in place. A plurality ofribbon fibers (six in all) are shown leading into splices 271 (showndarkened for clarity), and existing therefrom. A single fiber ribbon 272is shown darkened for clarity, coming from the storage space belowadapter plate 59 and entering channel 208. Ribbon 272 emerges fromchannel 208 and passes within to curved end walls of tray 196, thendiagonally crosses over, as depicted by the arrow, passing under insert237 and shelf 228 to circle around the opposite end as indicated by thearrow. Curved member 229 insures that the ribbon encounters no sharpedges. It then proceeds to the other end which it circles around, asindicated by the arrows, and then passes into the splice holder 238.Such a routing of the ribbon is made possible by the placement of thesplice holders on an elevated shelf, and provides a larger amount ofallowable fiber slack. As pointed out hereinbefore, with ribbons it isdesirable to have as much slack as can be accommodated.

The unique mass splice tray, 196 and the several components thereof asshown and described herein are the basis of U.S. patent application Ser.No. 08/851,102 of Burek et al., filed concurrently herewith.

The foregoing description and the accompanying drawings have been forpurposes of illustrating, in a preferred embodiment, the principles andfeatures of the present invention. The splice closure of the presentinvention and the several novel components thereof is capable ofhandling a wide variety of optical fiber cable types without thenecessity of customizing to accommodate particular cable types. Further,the closure affords ample storage for fiber slack, and can accommodatelarge numbers of fiber splices in a sealed enclosure having readyaccessibility to the splices.

It should be noted that it will be obvious to those skilled in the artthat many variations and modifications may be made to the preferredembodiment without substantial departure from the principles of thepresent invention. It is intended that all such variations andmodifications be included herein as being within the scope of thepresent invention. Further, in the claims hereinafter set forth, thecorresponding structures, materials, acts, and equivalents thereof andof all means or step plus function elements are intended to include anystructure, materials, or acts for performing the functions with otherelements as specifically claimed.

We claim:
 1. A racetrack grommet for providing a seal between first andsecond flanged closure portions wherein the closure portions define atleast one opening in the end which, when the portions are assembled,allow ingress and egress of at least one cable, said racetrack grommetcomprising:a member having first and second longitudinal sides spacedapart a distance such that they fit between the flanges on the first andsecond flanged closure portions; each of said longitudinal sides havinga first end and a second end, and transverse sections extending betweensaid first ends and said second ends; at least one insert receivingmember in at least one of said transverse sections and having a boreextending therethrough; first and second insert members for insertioninto said bore of said one insert receiving member in abuttingrelationship; each of said first and second insert members having alongitudinal bore extending therethrough for containing a cable; andholding means within said bore of said insert receiving member forholding in place said first and second insert members in buttingend-to-end relationship.
 2. The racetrack grommet as claimed in claim 1wherein said insert receiving member is cylindrical in shape and has anouter surface adapted to be clamped between said first and secondclosure portions.
 3. The racetrack grommet as claimed in claim 2 whereinsaid insert receiving member has a longitudinal slit therein extendingfrom said outer surface to said bore thereof.
 4. The racetrack grommetas claimed in claim 1 wherein each of said first and second insertmembers is cylindrical in shape and has an outer surface adapted to fitwithin said bore of said insert receiving member.
 5. The racetrackgrommet as claimed in claim 4 wherein each of said first and secondinsert members has a longitudinal split therein extending from its outersurface to said longitudinal bore.
 6. The racetrack grommet as claimedin claim 1 wherein said grommet is made of a flexible resilientmaterial.
 7. The racetrack grommet as claimed in claim 6 wherein saidmaterial is polyurethane.
 8. The racetrack grommet as claimed in claim 1wherein said first and second inserts are made of a flexible resilientmaterial.
 9. The racetrack grommet as claimed in claim 8 wherein saidmaterial is polyurethane.
 10. A racetrack grommet for providing a sealbetween first and second flanged closure portions wherein the closureportions define at least one opening in the end which, when the portionsare assembled, allow ingress and egress of at least one cable, saidracetrack grommet comprising:a member having first and secondlongitudinal sides spaced apart a distance such that they fit betweenthe flanges on the first and second flanged closure portions; each ofsaid longitudinal sides having a first end and a second end, andtransverse sections extending between said first ends and said secondends; at least one insert receiving member in at least one of saidtransverse sections and having a bore extending therethrough; first andsecond insert members for insertion into said bore of said insertreceiving member; each of said insert members being cylindrical in shapeand having an outer surface adapted to fit within said bore of saidinsert receiving member; and having a longitudinal bore extendingtherethrough for containing a cable; holding means within said bore ofsaid insert receiving member for holding in place said first and secondinsert members in butting end-to-end relationship, said holding meanscomprising a first V-shaped groove in the wall of said bore and a secondV-shaped groove in the wall of said bore spaced from said first V-shapedgroove.
 11. The racetrack grommet as claimed in claim 10 wherein thespacing between said first and second V-shaped grooves is approximatelyequal to the length of one of said inserts.
 12. The racetrack grommet asclaimed in claim 10 wherein each of said first and second inserts has aV-shaped ridge on said outer surface thereof.
 13. The racetrack grommetas claimed in claim 12 wherein said V-shaped ridge is dimensioned to fitwithin one of said V-shaped grooves in said bore of said insertreceiving member.
 14. The racetrack grommet as claimed in claim 12wherein each of said first and second inserts has first and second ends,and said V-shaped ridge is approximately centrally located between thesaid first and second ends.
 15. A racetrack grommet for providing a sealbetween first and second flanged closure portions wherein the closureportions define first and second spaced openings in one end thereof andthird and fourth openings in the other end thereof and an endcompartment adjacent each opening which, when the portions areassembled, allow ingress and egress of cables, said racetrack grommetcomprising:a substantially rectangularly shaped member having first andsecond longitudinal sides spaced apart a distance such that they fitbetween the flanges of the first and second flanged closure portions;each of said longitudinal sides having a first end and a second end; afirst transverse section extending between said first ends and a secondtransverse section extending between said second ends; first and secondlaterally spaced insert receiving members in said first transversesection and third and fourth laterally spaced insert receiving membersin said second transverse section; each of said insert receiving membershaving an axial bore extending therethrough; first and second insertmembers each having a longitudinal bore extending therethrough forcontaining a cable; holding means within said bore of each of saidinsert receiving members for holding in place said first and secondinsert members in butting end-to-end relationship within said axial boreof each of said insert receiving members; and mating means on each ofsaid insert members for cooperating with said holding means to retainsaid first and second insert members in place, said mating means andsaid holding means creating a substantially moisture proof seal betweensaid insert receiving member and said inserts.
 16. The racetrack grommetas claimed in claim 15 wherein each of said insert receiving members iscylindrical in shape and has an outer configuration adapted to fitwithin an end compartment of the closure when assembled and to beclamped between the first and second closure portions.
 17. The racetrackgrommet as claimed in claim 16 wherein each of said insert receivingmembers has a longitudinal slit therein extending from said outersurface to said bore thereof.
 18. The racetrack grommet as claimed inclaim 16 wherein each of said first and second insert members iscylindrical in shape and has an outer surface adapted to fit within saidaxial bore of said insert receiving member into which said insertmembers are to be inserted.
 19. The racetrack grommet as claimed inclaim 18 wherein each of said first and second insert members has alongitudinal slit therein extending from its outer surface to saidlongitudinal bore therein.
 20. The racetrack grommet as claimed in claim15 wherein said first and second spaced insert receiving members have aweb extending therebetween and said third and fourth insert receivingmembers have a web extending therebetween, said webs being adapted to beclamped between the ends of the first and second closure portions toproduce a seal therebetween.
 21. The racetrack grommet as claimed inclaim 15 wherein said grommet and said insert members are made of aflexible resilient material.
 22. The racetrack grommet as claimed inclaim 21 wherein said material is polyurethane.
 23. The racetrackgrommet as claimed in claim 15 and further including at least one portplug member having a cylindrical outer surface for insertion into one ofsaid insert receiving members,said port plug member having an outersurface having mating means thereon for mating with said holding meansin said insert receiving member.
 24. The racetrack grommet as claimed inclaim 23 wherein said mating means is a circumferential V-shaped ridge.25. The racetrack grommet as claimed in claim 23 wherein said port plugis a substantially hollow cylindrical having at least one closed end.26. The racetrack grommet as claimed in claim 25 wherein said port plugis made of a rigid plastic material.
 27. A racetrack grommet forproviding a seal between first and second flanged closure portionswherein the closure portions define first and second spaced openings inone end thereof and third and fourth openings in the other end thereofand an end compartment adjacent each opening which, when the portionsare assembled, allow ingress and egress of cables, said racetrackgrommet comprising:a substantially rectangularly shaped member havingfirst and second longitudinal sides spaced apart a distance such thatthey fit between the flanges of the first and second flanged closureportions; each of said longitudinal sides having a first end and asecond end; a first transverse section extending between said first endsand a second transverse section extending between said second ends;first and second spaced insert receiving members ins aid firsttransverse section and third and fourth spaced insert receiving membersin said second transverse section; each of said insert receiving membersbeing cylindrical in shape having an axial bore extending therethroughand having an outer configuration adapted to fit within an endcompartment of the closure when assembled and to be clamped between thefirst and second closure portions; first and second insert membershaving a longitudinal bore extending therethrough for containing acable; each of said first and second insert members being cylindrical inshape and having an outer surface adapted to fit within said axial boreof said insert receiving member into which said insert members are to beinserted; holding means within said bore of each of said insertreceiving members for holding in place said first and second insertmembers in butting end-to-end relationship, said means comprising firstand second V-shaped grooves in the wall of said axial bore, said groovesbeing longitudinally spaced from each other; and mating means on each ofsaid insert members for cooperating with said holding means to retainsaid first and second insert members in place, said mating means andsaid holding means creating a substantially moisture proof seal betweensaid insert receiving members and said inserts.
 28. The racetrackgrommet as claimed in claim 27 wherein said mating means on each of saidinsert members comprises a circumferential V-shaped ridge on the outersurface thereof.
 29. The racetrack grommet as claimed in claim 28wherein said V-shaped ridge is dimensioned to fit within one of saidV-shaped grooves and mate therewith.
 30. The racetrack grommet asclaimed in claim 24 wherein each of said insert members has first andsecond ends, and said V-shaped ridge is approximately centrally locatedbetween said first and second ends.
 31. The racetrack grommet as claimedin claim 30 wherein the spacing between said first and second V-shapedgrooves is approximately equal to the length of one of said insertmembers.